- vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 41604] GRB 260120A: GECAM-B observation
by GCN Circulars 23 Jan '26

23 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43505 SUBJECT: GRB 260120A: GECAM-B observation DATE: 26/01/23 15:39:23 GMT FROM: guohx(a)ihep.ac.cn Hao-Xuan Guo, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-B was triggered in-flight by GRB 260120A, at 2026-01-20T04:01:55.800 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #43467). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 2.3 +1.1/-0.7 s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecambgrb260120A.png Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS). View this GCN Circular online at https://gcn.nasa.gov/circulars/43505. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41603] GRB 260120B: AstroSat CZTI detection
by GCN Circulars 23 Jan '26

23 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43504 SUBJECT: GRB 260120B: AstroSat CZTI detection DATE: 26/01/23 12:52:45 GMT FROM: Anuraag Arya at IIT Bombay <aryaanuraag910(a)gmail.com> A. Goyal (IITB), A. Arya (IITB), M. Tembhurnikar (IUCAA), S. Salunke (IUCAA), Harsha K. H. (IUCAA), G. Waratkar (Caltech/IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long GRB 260120B which was also detected by Swift BAT (M. Ferro et. ala, GCN Circ. 43479), Fermi GBM (Fermi GBM Team, GCN Circ. 43477), Swift XRT (Goad et al., GCN Circ. 43484), and SVOM/C-GFT (Wu et al., GCN Circ. 43483). The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2026-01-20 18:00:23.85 UTC. The measured peak count rate associated with the burst is 312 (+129, -23) counts/s above the background in the combined data of three quadrants (out of four), with a total of 622 (+153, -176) counts. The local mean background count rate was 174 (+4, -6) counts/s. Using cumulative rates, we measure a T90 of 5.0 (+1.5, -1.5) s. The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-01-20 18:00:22.68 UTC. The measured peak count rate associated with the burst is 333 (+65, -44) counts/s above the background in the combined data of all quadrants, with a total of 1026 (+266, -251) counts. The local mean background count rate was 1065 (+7, -9) counts/s. We measure a T90 of 4.3 (+1.6, -1.8) s from the cumulative Veto light curve. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb View this GCN Circular online at https://gcn.nasa.gov/circulars/43504. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41602] GRB 260114A: Insight-HXMT/HE detection
by GCN Circulars 23 Jan '26

23 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43503 SUBJECT: GRB 260114A: Insight-HXMT/HE detection DATE: 26/01/23 11:58:54 GMT FROM: renyz16607(a)163.com Yang-Zhao Ren, Chen-Wei Wang, Cheng-Kui Li, Shao-Lin Xiong, and Chao Zheng (IHEP) report on behalf of the Insight-HXMT team: At 2026-01-14T11:40:26.300 (T0), Insight-HXMT/HE detected a short burst, GRB 260114A, which is also detected by Fermi/GBM (Fermi GBM team, GCN #43395), Swift/BAT (Eyles-Ferris et al., GCN #43396), GECAM-B (Ren et al., GCN #43402), SVOM/GRM (Wang et al., GCN #43404), and Konus-Wind (Ridnaia et al., GCN #43413). The Insight-HXMT/HE light curve mainly consists of multi-pulses with T90 of 0.28 +0.02/-0.02 s. The 1s peak rate, measured from T0-0.09 s, is 3104 cnts/sec. Insight-HXMT/HE detected a total of 3038 counts from this burst. The Insight-HXMT /HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb260114A.png All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the regular mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org View this GCN Circular online at https://gcn.nasa.gov/circulars/43503. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41601] GRB 260122B: Swift detection of a burst
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43502 SUBJECT: GRB 260122B: Swift detection of a burst DATE: 26/01/22 23:49:28 GMT FROM: Mike Siegel at PSU/Swift MOC <siegel(a)swift.psu.edu> A. Mei (INAF-OAB), R. Brivio (INAF-OAB), R. Gupta (NASA GSFC), A. Y. Lien (U Tampa) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 23:13:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 260122B (trigger=1443066). Swift did not slew immediately to the burst due to observing constraint. The BAT on-board calculated location is RA, Dec 336.079, -59.167 which is RA(J2000) = 22h 24m 19s Dec(J2000) = -59d 10' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 15 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger. We note that the burst occurred during the high background interval near the SAA. Therefore, at this moment we cannot completely rule out the possibility that the event is due to background fluctuation. However, given that the image significance is 9.35 sigma, we believe this is likely a real burst. Further ground data is required to determine the nature of the burst. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 2026 February 16. There will thus be no XRT or UVOT data for this trigger. Burst Advocate for this burst is A. Mei (alessio.mei AT inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) View this GCN Circular online at https://gcn.nasa.gov/circulars/43502. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41600] Swift GRB260122.97: Global MASTER-Net observations report
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43501 SUBJECT: Swift GRB260122.97: Global MASTER-Net observations report DATE: 26/01/22 23:22:27 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-SAAO robotic telescope [1] located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB260122.97 (trigger No 1443066,22h 24m 18.96s , -59d 10m 01.2s, R=0.05) errorbox 84 sec after notice time and 187 sec after trigger time at 2026-01-22 23:16:17 UT, with upper limit up to 15.9 mag. The observations began at zenith distance = 87 deg. The sun altitude is -38.0 deg. The galactic latitude b = -50 deg., longitude l = 331 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3112208 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 207 | MASTER-SAAO | P\ | 40 | 15.9 | The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43501. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41599] EP260119a: Assy AZT-20 optical observations
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43500 SUBJECT: EP260119a: Assy AZT-20 optical observations DATE: 26/01/22 12:09:42 GMT FROM: Alina Volnova at IKI RAS <alinusss(a)gmail.com> A. Volnova (IKI), A. Pozanenko (IKI), M. Krugov (FAI), N. Pankov (IKI) report on behalf of IKI-GRB-FuN: We observed the field of the EP260119a (Jiang et al., GCN 43447; GCN 43465; Cheng et al., GCN 43449) at the redshift of z ~ 5.47 (Corcoran et al., GCN 43469) with the AZT-20 telescope of Assy-Turgen observatory starting on 2026-01-20 (UT) 14:53 and taking several 60-second exposures in i' filter. In the stacked frame we detect the optical counterpart (Fortin et al., GCN 43450; GCN 43455; Eyles-Ferris et al., GCN 43452; Moskvitin and Spiridonova, GCN 43463; Liu et al., GCN 43464; Ma et al., GCN 43466; Zheng et al., GCN 43468; Corcoran et al., GCN 43469; Bochenek and Perley, GCN 43472; Pankov et al., GCNs 43476, 43499; Jin et al., GCN 43496). Preliminary photometry and observational details are the following: Date UT start t-T0 Exp. Filter Obj. Err. UL Site/Telescope (mid,days) (n*s) (3sigma) 2026-01-20 14:53:00 1.63500 63*60 i' 22.7 0.2 23.2 Assy-Turgen/AZT-20 The photometry is based on several nearby SDSS stars (i-magnitudes) and is not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/43500. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41598] EP260119a: Mondy and SAO RAS optical upper limits
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43499 SUBJECT: EP260119a: Mondy and SAO RAS optical upper limits DATE: 26/01/22 10:50:53 GMT FROM: Alina Volnova at IKI RAS <alinusss(a)gmail.com> N. Pankov (IKI), A. Moskvitin (SAO RAS), A. Volnova (IKI), O. Spiridonova (SAO RAS), E. Klunko (ISTP), A. Pozanenko (IKI) report on behalf of the IKI-GRB-FuN collaboration: We observed the field of the EP260119a (Jiang et al., GCN 43447; GCN 43465; Cheng et al., GCN 43449) at the redshift of z ~ 5.47 (Corcoran et al., GCN 43469) using the AZT-33IK telescope of the Mondy observatory starting on 2026-01-20 (UT) 18:52:22 and 2026-01-21 (UT) 19:10:23, and the Zeiss-1000 of the SAO RAS starting on 2026-01-21 (UT) 03:05:44. In the stacked frame of each observational epoch we do not detect the optical source reported previously (Fortin et al., GCN 43450; GCN 43455; Eyles-Ferris et al., GCN 43452; Moskvitin and Spiridonova, GCN 43463; Liu et al., GCN 43464; Ma et al., GCN 43466; Zheng et al., GCN 43468; Corcoran et al., GCN 43469; Bochenek and Perley, GCN 43472; Pankov et al., GCN 43476; Jin et al., GCN 43496). Preliminary photometry and observation details are listed below: Date UT start t-T0 Exp. Filter Mag MagErr. UL Site/Telescope (mid,days) (n*s) (3sigma) 2026-01-20 18:52:22 1.80804 45x120 I n/d n/d 22.3 Mondy/AZT-33IK 2026-01-21 03:05:44 2.13449 8*300 Ic n/d n/d 21.9 SAO RAS/Zeiss-1000 2026-01-21 19:10:23 2.82417 52*120 I n/d n/d 21.7 Mondy/AZT-33IK Photometric data are based on nearby SDSS stars (I-magnitudes obtained using the 2005 Lupton transform) and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/43499. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41597] GRB 260122A: Fermi GBM Final Real-time Localization
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43498 SUBJECT: GRB 260122A: Fermi GBM Final Real-time Localization DATE: 26/01/22 09:44:17 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 09:33:43 UT on 22 Jan 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260122A (trigger 790767228.420398 / 260122398). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 307.8, Dec = -12.8 (J2000 degrees, equivalent to J2000 20h 31m, -12d 48'), with a statistical uncertainty of 6.5 degrees. The angle from the Fermi LAT boresight is 65.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260122398/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260122398/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260122398/… View this GCN Circular online at https://gcn.nasa.gov/circulars/43498. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41596] IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43497 SUBJECT: IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility DATE: 26/01/22 08:15:17 GMT FROM: Jannis Necker at DESY <jannis.necker(a)desy.de> Akshay Eranhalodi (DESY), Robert Stein (JSI), Jannis Necker (Leiden University), and Anna Franckowiak (Ruhr University Bochum) report, On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: As part of the ZTF neutrino follow up program (Stein et al. 2023), we observed the localization region of the neutrino event IceCube-260115A (Zegarelli et. al, GCN 43421) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2026-01-16 05:53 UTC, approximately 12.3 hours after event time. We covered 99.2% (8.2 sq deg) of the reported localization region. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019, Stein et al. 2021) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019) . We are left with one transient candidate by our pipeline within the 90.0% localization of the skymap. +--------------------------------------------------------------------------------+ | ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr | +--------------------------------------------------------------------------------+ | ZTF26aabnqai | AT2026azb | 145.5760425 | +13.0239392 | r | 21.08 | 0.15 | +--------------------------------------------------------------------------------+ ZTF26aabnqai was first detected on 2026-01-16 at an apparent magnitude of about 21 mag in r-band. The g-r color is around 0.5 mag. Forced photometry revealed previous detections up to a week earlier with a fading rate of about 0.5 mag per day. The host galaxy has a photometric redshift of 0.23 +/- 0.08 in Legacy Survey. During our latest observatiosn the transient was no longer detectable, consistent with continued fading. This makes the transients too faint for our spectroscopic programs. However, the color, fade time and inferred absolute magnitude are all broadly consistent with a Type Ia supernova. These are not expected to emit high-energy neutrinos and thus we consider ZTF26aabnqai unlikely to be related to IceCube-260115A. We further identify following quasars without contemporaneous flaring activity. The hosts of ZTF22aaejlfn (SDSS J094112.55+131224.9), ZTF25aadwsdp (SDSS J093659.79+124616.6), ZTF25aadxqgk (SDSS J094449.16+120545.5), and ZTF25aarudkx (SDSS J094755.84+125346.4) are listed in MILLIQUAS (Flesch et al., 2023). ZTF24abwkvpl was first detected on 2024-11-05. Its host, SDSS J093633.62+131948.5, is part of a selection of quasars by SDSS photometry (Richards et al., 2009). The hosts of ZTF25aaedxfb, and ZTF25aadxmes show red, AGN-like WISE colors with W1-W2>0.8 (Stern et al., 2012). ZTF25abttvfc was consistently detected over the last 100 days with varying brightness. ZTF18acqfhyp, ZTF25aadnych, and ZTF25aadoovh were sporadically detected before the neutrino arrival and are likely variable sources at the sensitivity limit. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; DESY, Germany; TANGO, Taiwan; UW Milwaukee, USA; LANL, USA; TCD, Ireland; IN2P3, France. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019). Alert filtering is performed with the nuztf (Stein et al. 2021, https://github.com/desy-multimessenger/nuztf ). View this GCN Circular online at https://gcn.nasa.gov/circulars/43497. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41595] EP260119a: Xinglong optical upper limit
by GCN Circulars 22 Jan '26

22 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43496 SUBJECT: EP260119a: Xinglong optical upper limit DATE: 26/01/22 03:29:52 GMT FROM: Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong(a)nao.cas.cn> Junjie-Jin (NAOC), Haiyang-Mu (NAOC), Sen-Liu (NAOC), Pengliang-Du (NAOC), Zhou-Fan (NAOC), Hong-Wu (NAOC) report: Following the detection of EP260119a by EP-WXT (GCN Circular 43447,GCN Circular 43452), we observed the field of EP260116a using the 2.16-m telescope at Xinglong Observatory, NAOC. We obtained 600s clear-band frames with a median time of 2026-01-19T18:38:00 hr after the EP trigger. No uncatalogued optical transient is detected in the stacked images within the 3 arcmin EP/WXT error circle (GCN Circular 43447), down to 5-sigma limiting magnitudes of z ~ 19.8(not good day with thin cloud and bad seeing), calibrated with Pan-STARRS sources in the field. Also there is no apparent brightening for the catalogued sources within the error circle. Based on the location of the report(GCN Circular 43452), the target was not observed. View this GCN Circular online at https://gcn.nasa.gov/circulars/43496. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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